fix some int <-> size_t mix for buffer sizes
fix some int <-> size_t mix for buffer sizes

could have led to some negative overflow on 32bit arch
(if it was not for the "total_size == (size_t)total_size" test)

Change-Id: I7640340b605b9c674d30dd58a1e2144707299683

keane83/BLE_IM,Aexyn/libwebp,abwiz0086/webm.libwebp,PKRoma/libwebp,comoyo/gonzo-libwebp,webmproject/libwebp,ttyangf/libwebp,Suvarna1488/webm.libwebp,PKRoma/libwebp,Aexyn/libwebp,imazen/libwebp,jacklicn/libwebp,altogother/webm.libwebp,appunite/libwebp,redengineer/libwebp,kleopatra999/webm.libwebp,cysp/libwebp,comoyo/gonzo-libwebp,matanbs/webm.libwebp,iniwf/webm.libwebp,rxl194/libwebp,Acidburn0zzz/webm.libwebp,PKRoma/libwebp,Tekserve/libwebp,dumganhar/libwebp,redengineer/libwebp,keane83/BLE_IM,rxl194/libwebp,kalli123/webm.libwebp,kleopatra999/webm.libwebp,jiehu5114/libwebp,ericmckean/webm.libwebp,jiehu5114/libwebp,abwiz0086/webm.libwebp,ya7lelkom/libwebp,webmproject/libwebp,reimaginemedia/webm.libwebp,yohunl/libwebp,comoyo/gonzo-libwebp,kim42083/webm.libwebp,imazen/libwebp,yohunl/libwebp,altogother/webm.libwebp,dumganhar/libwebp,zofuthan/libwebp,cysp/libwebp,zofuthan/libwebp,altogother/webm.libwebp,comoyo/gonzo-libwebp,Distrotech/libwebp,jacklicn/libwebp,matanbs/webm.libwebp,kleopatra999/webm.libwebp,zofuthan/libwebp,ericmckean/webm.libwebp,appunite/libwebp,kim42083/webm.libwebp,iniwf/webm.libwebp,kalli123/webm.libwebp,Tekserve/libwebp,ttyangf/libwebp,comoyo/gonzo-libwebp,matanbs/webm.libwebp,Tekserve/libwebp,appunite/libwebp,kim42083/webm.libwebp,matanbs/webm.libwebp,yohunl/libwebp,iniwf/webm.libwebp,ericmckean/webm.libwebp,yohunl/libwebp,gshORTON/webm.libwebp,kleopatra999/webm.libwebp,redengineer/libwebp,gshORTON/webm.libwebp,imazen/libwebp,dumganhar/libwebp,ya7lelkom/libwebp,appunite/libwebp,appunite/libwebp,altogother/webm.libwebp,kim42083/webm.libwebp,abwiz0086/webm.libwebp,ya7lelkom/libwebp,Tekserve/libwebp,jacklicn/libwebp,kalli123/webm.libwebp,webmproject/libwebp,cysp/libwebp,kalli123/webm.libwebp,jiehu5114/libwebp,imazen/libwebp,Aexyn/libwebp,ericmckean/webm.libwebp,abwiz0086/webm.libwebp,webmproject/libwebp,iniwf/webm.libwebp,Acidburn0zzz/webm.libwebp,ya7lelkom/libwebp,iniwf/webm.libwebp,Acidburn0zzz/webm.libwebp,reimaginemedia/webm.libwebp,Distrotech/libwebp,redengineer/libwebp,ttyangf/libwebp,Aexyn/libwebp,Aexyn/libwebp,redengineer/libwebp,Suvarna1488/webm.libwebp,abwiz0086/webm.libwebp,jiehu5114/libwebp,kleopatra999/webm.libwebp,PKRoma/libwebp,webmproject/libwebp,reimaginemedia/webm.libwebp,gshORTON/webm.libwebp,jiehu5114/libwebp,Acidburn0zzz/webm.libwebp,imazen/libwebp,kalli123/webm.libwebp,ya7lelkom/libwebp,Suvarna1488/webm.libwebp,reimaginemedia/webm.libwebp,Acidburn0zzz/webm.libwebp,appunite/libwebp,Maria1099/webm.libwebp,rxl194/libwebp,rxl194/libwebp,cysp/libwebp,ericmckean/webm.libwebp,Maria1099/webm.libwebp,ttyangf/libwebp,PKRoma/libwebp,keane83/BLE_IM,zofuthan/libwebp,altogother/webm.libwebp,yohunl/libwebp,comoyo/gonzo-libwebp,keane83/BLE_IM,matanbs/webm.libwebp,gshORTON/webm.libwebp,Maria1099/webm.libwebp,PKRoma/libwebp,Maria1099/webm.libwebp,zofuthan/libwebp,jacklicn/libwebp,Maria1099/webm.libwebp,comoyo/gonzo-libwebp,ttyangf/libwebp,jacklicn/libwebp,gshORTON/webm.libwebp,rxl194/libwebp,reimaginemedia/webm.libwebp,keane83/BLE_IM,Distrotech/libwebp,kim42083/webm.libwebp,Suvarna1488/webm.libwebp,Suvarna1488/webm.libwebp